This study's aim was to determine relevant factors that influence the time interval between first induction and fetal expulsion in late termination of pregnancy (TOP) and TOP after previous feticide for severe fetal malformation with a mifepristone-misoprostol regime. This retrospective study included 913 TOPs from a single tertiary care referral center. In 197 out of 913 TOPs, a previous feticide had been performed due to advanced gestational age (after 22 + 0 weeks of gestation). Induction was accomplished using 600 mg mifepristone followed by 400 μg misoprostol. The interval between first induction with misoprostol and fetal expulsion was examined. Univariate and multivariate logistic regression analysis were used to predict an induction interval of 12 h or less. The median gestational age at induction of labor was 18.9 weeks of pregnancy. In 487 (53.3%) cases women delivered within 12 h; in 344 (37.7%) cases the induction interval was between 12 h and 36 h. In 82 (9%) cases induction took longer than 36 h. Factors that were significantly associated with a delivery duration of <12 h were a lower gestational age at induction (OR 0.87; 95% CI 0.84-0.89; p < 0.001) and a history of at least one previous vaginal delivery (OR 1.57; 95% CI 1.20-2.05; p < 0.001). Factors that had no impact included previous cesarean section, performing feticide before induction and maternal age. Maternal BMI showed a non-significant trend.
Keywords: fetal expulsion; fetal malformation; feticide; genetic abnormalities; induction of labor; mifepristone; misoprostol; termination of pregnancy.